mozilla/connect-cachify — comment on commit b85c91d5ce7f6fc4e7682e1091c24d6fb19afe29
File: lib/connect-cachify.js line 92
By ozten:

If no other middleware sets headers, this event handler would never run. We'll want to explicitly set headers we rely on, and clean headers we don't want.

I didn't see removeHeader throwing an exception, but I think this is more bulletproof in case that behavior changes (or was different in the past).